Means for controlling the supply of a driving fluid, the pressure of a fluid, and similar purposes



Dec. 3, 1929. T, KALLE 1,738,072

MEANS FoR CONTROLLING THE SUPPLY OF A DRIVING FLUID, THE PRESSURE OF AFLUID, AND SIMILAR PURPOSES Filed D60. 28, 1923 13109112721 T Kalle litPatented Dec. 3, 1929 UNITED STATES TORSTEN KALLE, OF SAFELE, SWEDENMEANS FOR CONTROLLING THE SUPPLY OF A DRIVING FLUID, THE PRESSURE AFLUID, AND SIMILAR PURPOSES Application filed December 28, 1923, SerialNo. 683,261, and in Sweden January 2, 1928.

.the carrier, the parts at each side being connected with a mountingcommon to the same, the said mountings preferably comprising astationary support and a movable member to which, 'lor example, a valveor the like to be controlled is connected. Dwing to this arrangement theconductor will have a tensile strength equal to the sum of the tensilestrengths of all the parts thereof, so that the device may directlyoperate even a heavy valve or the like to be controlled.

ln the accompanying drawing Figure 1 shows one example of theelectro-thermic device combined with a servo-motor for controlling thepressure in a steam conduit. Figure 2 shows a side view of theelectro-thermic device together with a Bourdon-tube and a contact devicefor effecting the control. Figure 3 is a plan view of theelectro-thermic device.

The electro-thermic device comprises a bare conductor 41, which for thenecessary turns is wound round a plate 42 and insulated from the same,the plate being provided with notches for supporting the conductor. Thetop parts of the conductor 41 are connected with an insulating member43, fixed to a casing 40 of inverted L-shape (Fig. 1) enclosing thecontrolling device, while the lower parts of the conductor are fixed toanother insulating member 44. By a .spring device acting upon the-member44, the parts of the wire 41 are subjected to a straining action, sothat the upper set of parts and the lower set of parts of the conductorform preferably acute angles with each other as shown in Figure 2. As anelectric current of varying strength or elec tric impulses passesthrough the conductor 41, the temperature of the latter varies, whichresults in the length of the conductor being changed, so that the member44 is moved towards the member 43 or from the same. In the controllingdevice shown in the drawing the movement of the member 44 is used foroperating a valve 9, which controls the discharging ot the pressureliquid from a servomotor 1. The servo-motor comprises a cylinderprovided with a supply pipe for pres" sure-liquid and a piston, the rodout which by a wire 2, chain or the like is connected with the valve oia steam conduit 50. A counter-weight 7' tends to move the valve towardsits closed position. Member 44 car ries a bolt 45 in screw-threadedengagement with a nut 46. Between the nut 46 and the bottom wall of thecasing 40 a coil spring '47 is provided. By means of the nut 46 thetension of the spring 47 and thus the tension of the parts oi theconductor 41 may be adjusted. Nut 46 has a pin 46 bearing against thespindle of the valve 9. The latter is so arranged, that it may be openedto a greater or less extent by the pressure liquid of the servo-motor itagainst the action of the spring 47. The distance for which the valve isopened is determined by the electro-thermic device, as will be explainedhereinafter.

A Bourdon-tube 48 communicates through a pipe 49 with the steam-pipe 50.A twoarmed lever 51 is pivoted to the free end of the tube 48 andcarries at its one end an arm 52 provided with a contact 58 for instanceof copper, which co-operates with a contact 54 for instance of carbon.Contact 54 is fixed to the carrier 42 and connected with one of the endsof the conductor 41. The other end of the conductor 41 is connected withthe socket 57 of a plug, connected for instance with the positive leadof a source of current, while the negative lead is connected with thecasing 40 or the arm 52. To the other end oi the arm 51 a spring isconnected, which may be adjusted by a screw 56. By changing the tensionof the spring 55 the steam-pressure is adjusted, for which the deviceought to eilect its controlling action. The distance between thecontacts 53, 54 is adjusted by means of a screw 58, provided on the arm52 and bearin against the tube 48.

The evice operates in the following manner. If the steam-pressure in thepipe 50 increases, the Bourdon-tube 48 moves the contact 53 from thecontact 54. Conductor 41, previously heated by the current, then becomescooler and conse uently shorter, which results in the pin 46* eingraised and the valve 9, acted upon by the pressure liquid in theservo-motor, being moved into a more open position against the tensionof the spring 47. The liquid below the piston of t e servo-motor thenescapes for a greater quantity, thus permitting the said piston to movedownwards and the weight 7 to move the valve 35 towards its closedosition, so that the pressure of the steam ehind the valve is reduced.By the contraction of the conductor 41 also the plate 42 is raised,which results in the contact device 53, 54 being again closed, providedthat the increasing 0 the steam-pressure and thus the raising of thecontact 53 was within certain limits. As the contact device is closed,the temperature and the length of the conductor 41 are increased, sothat the valve 9 is moved towards its closed position by the spring 47.The pressure liquld then raises the piston of the servo-motor, so thatthe valve 35 is moved towards its open position and the steamsressurebehind the valve and in the Bouron-tube is somewhat increased. Thisresults in a new breaking of the contact-device 53, 54, a new coolingand contraction of the conductor 41, the moving of the valve 9 to a moreopened position and so on. The described operations are repeated until astate Y of equilibrium of the members belonging to the controllingdevice is created and the valve 35 is brought into a position in whichthe steam-pressure in the tube 50 has been adjusted to the desiredamount. The said state of equilibrium will be maintained while thedistance between the contacts 53, 54 is increased and decreasedalternately. The controlling device operates in an exactly analogousmanner if the pressure in the pipe 50 alls below the normal. Valve 9 isthen successively moved towards its closed position, so that theservo-motor successively brings the valve 35 into a more open position.

Owing to the fact that the conductor 41 is wound round the carrier 42for a number of turns, the conductor is so long that it may be connecteddirectly with a network of high tension circuits without a seriesresistance. At the same time the tensile stren th of the wire isincreased, as it is equal to t e sum of the tensile strengths of all thecoils, the force exerted by the conductor, when cooled, being thussufiicient for operating, for instance, the throttling device of a steamconduit directly, without the aid of a servo-motor. Preferably theconductor 41 is so thin, that the changin of its temperature and thus ofits length ta es place as nearly momentarily as possible at the changingof the intensity of the current or at the passing of the currentimulses.

claim:

In an electro-thermic controlling device adapted especially for shiftingheavy members such as valves and eflecting great movement of the samethe combination of a movable plate-shaped carrier, a conductor woundround the said carrier, a stationary mountin to which the Karts of theconductor locate at the one si e of the carrier are fixed, a movablemounting to which the parts of the conductor located at the other sideof the carrier are fixed, and means provided on the mounting lastmentioned for the connection of the member to be controlled.

In testimony whereof I have hereunto affixed my signature.

TORSTEN KALLE.

